Management of Acute Diarrhea with Systemic Symptoms

Immediate Rehydration

Initiate oral rehydration therapy as the first‑line intervention for every patient with acute diarrhea, irrespective of the presumed cause. 1
The presence of concurrent nausea or vomiting together with diarrhea markedly raises the risk of dehydration and warrants aggressive fluid replacement. 1
Assess for dehydration by checking for dizziness, excessive thirst, reduced urine output, and orthostatic changes in vital signs. 3

Recent travel to low‑ and middle‑income regions should raise suspicion for traveler’s diarrhea caused by enterotoxigenic E. coli, Campylobacter, Salmonella, or Shigella. 4
Consumption of raw or undercooked meat, raw seafood, or unpasteurized dairy products is a key exposure risk for bacterial enteric infections. 1
Stool characteristics that guide further work‑up include high frequency (≥3 stools/day), presence of blood, mucus, or melena‑type (black, tarry) stools. 1
Fever occurs in up to 30 % of infectious diarrheal episodes; its presence suggests an invasive bacterial pathogen and may indicate the need for antibiotics. 4
Systemic manifestations such as myalgia, especially when combined with gastrointestinal symptoms, should prompt consideration of viral gastroenteritis or COVID‑19. 5

Indications for fecal studies (any one of the following):

Recommended tests when indicated:

Stool culture for bacterial pathogens such as Salmonella, Shigella, and Campylobacter. 1
Complete blood count to detect leukocytosis that supports a bacterial etiology. 3
SARS‑CoV‑2 testing when gastrointestinal symptoms coexist with myalgia, loss of appetite, or known exposure. 5

Traveler’s diarrhea with moderate‑to‑severe symptoms: fluoroquinolone (e.g., ciprofloxacin 500 mg BID × 3 days) or azithromycin 1 g single dose. 1
Suspected shigellosis (bloody diarrhea, fever, abdominal cramps): fluoroquinolone or azithromycin. 1
Suspected Campylobacter infection, especially after travel to Asia where quinolone resistance is high: azithromycin 500 mg daily for 3 days. 4
Febrile dysentery (fever with bloody diarrhea): a third‑generation cephalosporin or fluoroquinolone. 4

Antimotility agents: Loperamide must be avoided in patients with bloody diarrhea, high fever, or suspected Shiga‑toxin‑producing E. coli. 1
Antiemetics: Ondansetron is recommended for severe nausea or vomiting that interferes with oral rehydration. 3

Diarrhea is reported in ~22 % of all COVID‑19 cases and in ~24 % of hospitalized patients. 5
The presence of gastrointestinal symptoms (diarrhea or nausea/vomiting) increases the odds of a positive SARS‑CoV‑2 test by roughly 70 %. 5
SARS‑CoV‑2 testing should be performed when GI symptoms are accompanied by respiratory signs or known exposure. 5

Severe dehydration (inability to maintain oral intake, oliguria, altered mental status). 3
Bloody stools. 1
High fever (> 39 °C/102.2 °F) or fever persisting > 48 hours. 1
Severe abdominal pain not relieved by defecation. 3
Peritoneal signs (rigid abdomen, rebound tenderness). 3

Most acute infectious diarrheas are self‑limited, resolving within 3–7 days.
Persistence of symptoms beyond 14 days defines “persistent diarrhea” and warrants re‑evaluation for alternative diagnoses (e.g., inflammatory bowel disease, chronic infection). 1